Colorado's public health director says officials don't know enough yet about what was in the smoke released from a Denver-area refinery after a power failure to determine if it was hazardous. They were still waiting as of Saturday.

However, Dr. Larry Wolk says authorities are reassured that Friday's release from the Suncor Energy, Inc. refinery was brief. He says it doesn't appear to pose any immediate threat to people nearby.

Heavy smoke was seen coming from the Suncor Refinery in Commerce City on Friday. The Denver Fire Department responded to assist Adams County with a hazmat incident in the 5600 block of Brighton Boulevard.

According to the Environmental Protection Agency, Xcel Energy was working on repairs at the plant. An incident occurred causing a power outage at the refinery around 12 p.m.

The refinery went into automatic shutdown. The orange and black smoke clouds seen around the metro area were the result of a "type of clay" used in processes at the refinery.

The Colorado Department of Public Health and Environment released a statement on the incident Friday afternoon.

Suncor is continuing to monitor the air around the facility.

Interstate 270 was closed in both directions from Interstate 70 to Interstate 76 for a short time. It has since reopened.

Brighton Boulevard is closed in both directions from 56th to 60th avenues.

According to their website, the Suncor Refinery is a 98,000-barrel-per-day refinery that produces gasoline, diesel fuel and paving-grade asphalt.